Computing sight for gliding torpedoes



S P 4 M. F. BATES 2,383,952: I

- COMPUTING SIGHT FOR GLIDING TORPEDOS Filed July 15, 1942 3 Sheets-Sheet l INVEVNTOR, MORTIMER F. BATES Sept. 4, 1945. BATES 2,383,952

COMPUTING SIGHT FOR GLIDING TORPEDOS Filed July ,15; 1942 3 Sheets-Sheet 2 lNVENTOR, MORTIMER F. BATES;

' IS ATTORNEY.

COMPUTING SIGHT FOR GLIDING ToRPEn'os Filed July 15, 1942 3 Sheets-Sheet 3 s ATTORNEY.

Patented Sept. 4, 1945 "m orr ca ooMeU'rrNG sron'r For; QGLIDING 'roarsnons Mortimer F. Bates, Brooklyn, Y.,a ssignr to Sperry Gyroscope Company, Inc., N. Y., a corporation of New York Brooklyn,

- 1 Application July 15, 1942, Serial No. 451,037, 14 Claims. 01. sag-ms) This invention relates to the art of aiming and launching .aircraft-borne under-water torpedoes, and refers more particularly to sighting and computing means adaptedito determine the proper launching point and aiming angles to cause a torpedo to collide with a floating target after traversing a course in water.

Early methods of attacking a marine target required that a 'tQrpedo-bearing aircraft descend toa very low altitude, often barely clearing the Water," before releasing a torpedo in order to insure that the torpedo, upon striking the water, would proceed in a stable manner along a predeterminedcourse set to cause collision with the target. More recently a method has been evolved which, by means of suitable wing and tail members, converts the torpedo, as launched, into a heavy weight glider with a definite flight path controlled by its gliding attitude, which is caused to be about 14 below the horizontal. The torpedo while in the air glides at a substantially constant speed along this path. In this manner, what was formerly the free fall of the torpedo from a very low altitude has been converted into a glide from a much higher altitude, for example, up to 4000 feet. As a result, not only is the permissible release point considerably higher, but the horizontal range is also considerably increased, both of which changes render the attacking crar't less likely to be hit by anti-aircraft fire from the target. Shortly before the torpedo enters the water, a trailing lanyard, through'a suitable release mechanism, disconnects the wing structure from the torpedo, which thereafter continues its journey under water at a predetermined speed and on the predetermined collision course.

According to the present invention, a computing mechanism is provided Which'obtain's," by simple mechanical means, a solution of the course setting problem presented, in this more recent method of launching, by the different course angles of the torpedo during its air glid and water run and by the factors which cause 'varia tions of these angles. There is further provided means for making angular settings of the index mirror of a reflex sighting device, for sighting the target. which take into account a predetermined angle of depression of the 'lineof sight belov. the horizon at the instant of torpedo release, the angle of lead or aim off angle necessary to compensate the torpedo aiming angles for the speed of the target, and the angular effect of cross wind. in deflecting the torpedo during its air glide. These various angles are determined ying' partly in air and partly by setting in the computing mechanism the factors or target "speed and'direction, torpedo speed,wind velocity and direction, and the desired releasealtitude. 1 e

To provide an index for the position of the target as seen through the reflex sight, a stabilized illuminated reticle isprovided whose image is projected to infinity in a direction determined by the index mirror setting.

Itjis an object of the invention to provide means adapted; to determine proper conditions for launching a torped -from a supporting body,a't a "substantial height; above the surfaceof the earth in agmanner to cause collision with-a marine tar- Another object isto; provide sighting and computing meansa-dapted to determine the angular relationships involved in launching and controlling; the-course of an aircraft-borne torpedo destinedfor collision with a terrestrial target after following a combination air and Water path.

Another object is to providecomputing means adapted to predetermine the angular position of the line of sight from an aircraft to a terrestrial target -at t the -proper instant for releasing; a torpedo to cause the torpedo to collide with the target after following a combination air and waterqpath.

Anotherobject :15 to provide, in connection with y the launching of a-gliding torpedo from an aircraft ata-substantial height above the surface of'the Water, meanspredetermining the proper courses of the torpedo during the air and water runs thereof to causecollision with a selected target,

Another objecti to determine and set such courses for the torpedo as will maintain an angle of constant-bearing relative to the target during both the air and Water runs.- 1

Another object is to provide means cooperative with the steering "mechanism of a torpedo, adapted to glide from an elevated point to the surface of the water, for presetting a desired change of courseupon entrance ofthe torpedo into the water. Another. object is to provide, in a computing sight for launching a gliding torpedo from an aircraft, a stabilized index of target position at the instant of release. Another object is to provide Wind compensating means in asight of the above character.

. Another object is to provide, in a sight of the above character, means for computing angular lead to'compensate for target movements.

Another object is to provide means predetermining the length of the desired water run of the torpedo.

Still another object is to provide means adapted to supply criteria for torpedo release at different altitudes.

Other objects and advantages of this invention will become apparent as the description proceeds.

In the figures,

Fig. 1 is a plan diagram showing the combination air and water path of the torpedo and the relation thereof totarget movements.

Fig. 2 is a similar diagram, in elevation.

Fig. 3 is a plan view of a computing sight according to the invention, including connecting means for setting the course of a torpedo.

Fig. 4 is a schematic diagram in perspective of the computing mechanism of the apparatus of Fig. 3.

Fig. 5 is a modification of a portion of the mechanism of Fig. 4.

Fig. 6 is an elevation, partly in section, of a stabilized reflex sight suitable for operation in connection with the computing mechanism of Fig. 4.

Fig. '7 is a detail of Fig. 6.

Fig. 8 illustrates sighting means remotely controlled from the computing mechanism.

Fig. 9 is a detail of Fig. 4.

Fig. 10 is a wiring diagram related to Fig. 9.

Referring to Fig. 1, there are shown, projected on a horizontal plane, the displacements of the torpedo during its air glide and water run and the corresponding displacement of the target. To determine the directions of these displacements auxiliary vector diagrams of velocities are also shown, superimposed on the displacement diagrams. Assuming now that at the moment of torpedo release the target is located at the point A and is proceeding along the course S, S, it is required that the torpedo collide with the target at some point C on the line S, S which the torpedo is to reach by an air run OB and a water run BC. According to the principles of the invention, during both of these runs displacement of the torpedo relative to the target is along a line of constant bearing with respect to the target course. In the diagram this constant bearing is the angle d between the target course S, S and the line of sight 0A and the torpedo therefore appears from the target to be moving toward collision, in plan projection, along a line parallel to 0A, during both the air and water runs.

Considering first the horizontal projection of the air run, thecourse of the torpedo, relative to the ground is determined by the angle of constant bearing together with the velocity and course of the target, which are assumed to be known or determinable (by means not forming a part of the invention) and the known horizontal component of the gliding velocity of torpedo. Assuming values for the two velocities and the course angle of the target, the course of the torpedo is found graphically, according to the construction in Fig. 1, as follows: From the point A and along the target course, a distance AD is measured proportional to target speed. From the point D an arc is struck having a radius equal to the assumed horizontal component of torpedo gliding speed, intersecting the line of constant bearing at O. The angle AOD, that is, the angle 2), is then the desired aim off angle, or the angle which the air course of the torpedo should make with direction of the line of sight, this angular lead ahead of the line of sight being necessary to compensate for target velocity, as in the case of gun fire against a moving target.

If the course of the torpedo were entirely in still air and if it were released at point 0 and at a suitable altitude, with the craft headed along the line OD, the torpedo would collide with the target at point D. Actually, however, instead of releasing at an altitude which would cause collision after a glide Wholly in air, an altitude is chosen which causes the torpedo to strike the water at some closer point B and at this point the torpedo course must be changed if the angle of constant bearing relative to the target course is to be maintained, because of the slower speed of the torpedo during its water run. Consequently, at point B the course of the torpedo is altered by the angle a which will be called the torpedo angle, determined as hereinafter described.

The course OD is the desired ground track of the torpedo, or course to be made good. However, during the air run from the point of release 0 to the point of entrance into the water B, the torpedo is deflected laterally from the course along which the craft is travelling at the instant of release in proportion to the existing cross wind. The course OD is therefore not the proper course along which the torpedo should be started off. Assume that the total wind or relative air speed has a magnitude and a direction indicated by the vector FD. A drift correction angle a to compensate for the component wind across the line of flight is determined b constructing the vector FD, proportional to wind, with its tip at the point D. The angle FOD is then the drift angle a, and the direction of OF is the course to be flown by the craft at the moment of release, the torpedo after release proceeding to drift sideways andthereby follow the course OD. All courses may be determined by reference to the compass or other datum which remains fixed relative to the ground.

The wind vector FD may be resolved into two components, FM along the course of the aircraft and DM perpendicular to this course, the two components being respectively referred to as the head wind and the cross Wind acting on the torpedo. Compensation for the effect of cross wind is had by changing the heading of the craft through the angle a, as has been described. The effect of opposing head wind is to cause the torpedo to strike thewater sooner than would otherwise be the case and thus, for a given release point, to lengthen the water run. To maintain a constant water run with constant altitude release, compensation for the effect of head wind may be made by changing the release point of the torpedo in a direction such that for an opposing wind this release point is moved nearer the target than would be the case in still air.

In Fig. 1, the point Oon the continuation of the line DO represents a virtual point of release in still air when the actual release point in the presence of the head wind FM is 0. It will be apparent that a different diagram corresponding to Fig. 1 must be constructed for each value of head wind.

The change of course through angle c at the point B is effected by suitably setting the torpedo rudder angle control before release. Angle 0 depends upon the ratio of the velocity of the target to the velocity of the torpedo during its water run. To construct this angle, a velocity triangle may be drawn having one side extending along the line of constant bearing OA and a second L' at an altitude L M.

side along the target course S, S. For convenience, in this case the already determined distance AE along line S, S is taken as the measure of target speed. To determine the direction of the third side of the triangle, from the point B (the intersection of S, S and OH) with a radius equal to the assumed water speed of the torpedo '(on the same scale as that of AE) an arc is struckintersecting the line CA at G. The line EG will have the direction of the water course ofthe torpedo, which may then be laid out from the point B, parallel to ES, to intersect the target course at C, the collision point.

- The angle is not the correct angular setting of the gyro which controls the torpedo rudder because, at the time of release, the aircraft is headed along the line OE, which is at the angle a to the ground track OB of the torpedo. Consequently, the gyro angle of the torpedo must be set" to take into account and to neutralize this additional drift angle, that is the actual gyro setting will be an angle equal to cia.

In Fig; 2, the displacements of the torpedo in a vertical plane are illustrated. As in the plan diagram of Fig. l, the release point in the presence of-opposing head wind is designated as O, the corresponding point in still air being 0'. leased at O, with no head wind the torpedo with its associated air foil structure would glide to the surface of the water along the path determined by its normal attitude of 14. If released in the presence of opposing head wind of magnitude FM (Fig. 1) the descent, relative to the ground, will be at a steeperangle as shown by the heavy line'OB, the point 0 being advanced ahead of O a suitable distance to maintain a constant Water runBC. The length of the water run depends upon the characteristics of the torpedo, tactical considerations, etc. and may be of the order of five to eight hundred yards.

.The angled which the line of sight makes with the horizon at the instant of release, termed the depression angle, is one whose cotangent is the product of range KA and altitude OK Consequently, range may be expressed as KA=OK cot d It will be seen that some choice of release altitude may be had by moving the release point up and down the glide path, as is shown (without compensation for head wind) by the point In any case, the sight is set so that the proper release point is indicated when the line of sight is on the target, this is, I

when the reticle markings appear to be centered on the target.

Referring now to Fig. l, there is shown the computing mechanism by means of which the angles related to the air and water runs of the torpedo and the reticle settings are determined. At the upper left of the figure a wind velocity and direction setting mechanism is shown comprising a compass card or disc i having compass markings thereon which is rotatably mounted and which may be angularly positioned by a handle or knob 2 on shaft 3 by way of worm i engaging teeth out in the periphery of the card. A crank arm 6 having a plurality of spaced holes or indentations 1 at radii respectively cor- Y responding to discrete settings of wind velocity over a predetermined range, is independently rotatable about the axis of rotation 9 of card i and may be locked to the card at any desired angular position or compass marking by means not shown. A pin in mounted at the extremity of a crank rod 12 is adapted to engage a selected depression 1 to set the effective radius of crank arm 6 at a value proportional to wind velocity. Crank rod ['2 is a materialization of the line OF of Fig. 1 while arm 6, as to its effective length, represents the wind vector FD. Rod 12 is in- "tegral with or rigidly attached to hub i3 of bevel gear i5 by. means of which one input motion is introduced into wind compensation differential l8.. Asecond input to said differential to be described hereinafter is by way of gear ll while theoutput is taken from shaft 2!, by way of bevel gears Hi, to actuate shaft 20 in proportion to net aim-off angle. Centrally positioned shaft 2! is journalled at one end in bracket 22 and forms a 'gudgeon pin for translating the crosshead structurecomprising bed plates or carriages 25 and 2-6. 7

Axis 9 of card I is fixed and the horizontal line connecting this axis and the axis of pin 2| is the base line of the wind compensation mechanism, corresponding to the line OD of Fig. 1. Plate 25 is guided by guides 2'1 and other members not shown for translation parallel to this base line.

Plate 25 is similarly guided and moves with plate 25 but in addition has an independent adjustment to be described hereinafter.

Meshing with gear l5 of differential I6 is a gear 28 carried by a rod 30 which extends parallel to the base line of the wind compensation mechanism. Rod 38 is splined at the end thereof opposite gear 28 for sliding engagement with bevel gear 32 meshing with gear 33 mounted for rotation with gear 34 which in turn meshes with gear 35 in one arm of differential 36. A-second arm of diiferential 36 is connected by way of gearing 31 to gyro angle setting knob Ml and gyro angle setting shaft which mounts an indicating dial 46, readable on a stationary index 41, while a third arm has a connection by way of gears 38 to shaft 4i} carrying yoke 4| of the torpedo angle setting mechanism.

With arm Bclamped'to card i at a compass marking corresponding to the direction of the existing wind and with pin ill engaging a depression l at a radius representing the magnitude of the total wind, the orientation of card I in correspondence with the compass, accomplished by rotating knob 2 until a stationary index (l2 indidrift angle, a. Displacement of shaft 35 is trans mitted to differential 3'5 where the torpedo gyro angle 0, is added (as hereinafter described) by rotation of knob it. The output motion of differential 3S, representing the algebraic sum of angles a and c, is transmitted to the torpedo gyro angle setting mechanism by a connection to shaft 45. A dial it-and index l! is provided for shaft 45.

In the mechanical representation of the several triangles of Fig. 1, it is not convenient to superimpose the diagrams associated with drift and aim-off angles but instead these triangles are set up in parallel planes. Thus the triangle which includes the aim-off angle b is set up below the wind triangle representation just described and has, as a materialization of the side 0A, the

rod 50 having an effective length measured from a pin 52, rotatably engaging one end of the rod and the axis of rotation of a swivelling guide block 53 in which the opposite end slides. The side AD of the aim-off triangle, 1. e., target velocity, is represented by a line connecting the axis of pin 52 and that of shaft 49. The third side of the triangle, the fixed-length base OD, is then-- represented by a horizontal line connecting the axis of shaft 59 (coincident with the axis 9 of card I) and the axis of gear 54 meshing with gear I7, the latter axis intersecting the axis of rod 59. The vertex of the aim-oil? triangle is thus offset from the corresponding vertex of the wind correction triangle, laterally, by the distance between the centers of gears I! and 54.

The setting of the magnitude and direction of target speed AD in the mechanical scale representation of triangle AOD is accomplished by means now to be described:

Pin 52, which is shown greatly elongated for clearance of illustration, is mounted, at the end thereof opposite that at which it engages rod 59, in a carriage 55 which is in threaded engagement with a screw 56 and restrained by guides (not shown) to displacement parallel to the axis of the screw. Screw 55 is journalled in a positionable frame 5? and rotated from a crank handle 58 by way of shaft 59, gears 6!, 52, 63, shaft 65 and bevel gears 65. Rotation of handle 58 is thus caused to change the effective crank arm of pin 52 relative to the axis of shaft 65, which is coincident with the axis of shaft 49 and axis 9 of card I. Since the radial position of pin 52 is a measure of target speed, a counter 61 may be geared to shaft 69 to indicate such speed in suitable units such as knots.

The setting of target course is made by means of a knob or handle 68 which rotates a dial IO through a Worm drive 59. Dial 19 has a representation of a target ship in miniature, the bow of the ship serving as an index readable on a fixed scale I2. Dial I9 is rotatable about shaft 60 and carries with it a gear is driving, through idler gear i l, a second gear 75 mounted on a sleeve I6 rotatable about shaft 55. Sleeve I6, at the upper end thereof mounts frame 51 Which is thereby angularly positioned in correspondence with dial- Ill. Rotation of knob 68 is prevented from affecting the magnitude of the speed setting by making the gear ratios of GI, 53 and of I3, 75 equal. Shaft 69 being caused to rotate with dial I9 and gear 13 by frictional drag, no relative motion between shaft 65 and sleeve I6 occurs to rotate screw 56.

By the settings of target speed and course introduced by cranks 58 and 68 respectively, pin 52 is offset from the axis of shaft 55 in a direction and by an amount which cause the offset to represent the vector AD of Fig. 1. As pin 52 is moved the resulting displacement of the left-hand end of rod 55 causes a rotation. of guide block 53, which is mounted on a shaft IT journalled at one end in bracket is on bed plate 25 and which carries with it gear as meshing with gear ll of differential I5. Thus the angular position of shaft TI is made proportional to the angle b of Fig. l and by means of differential I 6 the value of this angle is combined with the value of angle a introduced by way of rotatable rod or shaft 39 to cause the position of output shaft 26 to be proportional to the algebraic sum of the angles a and b, that is proportional to the net aim-off angle or net angu lar lead of the course of the craft at release relative to the line of sight.

v.Ihe third triangle of Fig. 1 which is represented to scale by the mechanism of Fig. l'is the triangle AGE from which the water course of the torpedo is determined. A portion of rod 59, and an arm 89 which engages the rod, form respectively the sides AG and EG of this triangle. Arm 89 at one end is provided with a contact arrangement 85-8'I, Fig. 9, which may be set in sliding engagement With contact rails I8I-I8I' carried by an enlarged portion of rod 55. The opposite end of arm 89 has a rack formed thereon which meshes with a gear formed on a drum shaped member 82. Arm 8!! is suitably guided so that the rack thereon is maintained in mesh with the gear. The member 82 is supported on a shaft held between the arms of yoke GI, the shaft being offset from shaft 40 which turns the yoke. The point E of the triangle is the point on arm 89 tangent to drum shaped member 82. The elfective length of arm may be adjusted by rotating member 82. Yoke 4| may be turned to cause arm to describe an are for the purpose of bringing the contact mem-- bers 85-87 of the arm and those of rod 50 into engagement.

The length of arm 89 may be adjusted by turning a worm screw 8! (in bearings not shown), by means of a screwdriver. Worm 8|, whose position in terms of torpedo water speed is readable on a scale 85 on drum 82, meshes with teeth on the upper portion of drum-shaped member 82 rotatably mounted in yoke 4| while other teeth on the lower portion of member 82 mesh with rack teeth out in arm 89. This arm which is suitably guided, at the rack end thereof, in yoke 4|, bears at the opposite end a pin 85.

- This detail of the mechanism is better seen in Fig. 9. Pin 85, carrying a rounded contact 81, is guided by a sleeve I85 which is insulated from arm 80 by bushing I84. Pin 85 is urged downwardly by spring I85, with a collar I88 limiting its displacement. An enlargement of rod 50 carries a pair of contact rails IBI, I8I', insulated therefrom by a member I89, which serve both as contact meansand as a detent for pin 85. In fixing the direction of the water course (lines EG and B0 of Fig. 1) arm 89 is rotated by rotating knob l until contact 87! drops into the depression between rails I8I, I85 at which instant a circuit is completed causing a lamp 83 to light up, as will be apparent from the circuit of Fig. 10. The described operation sets the angle 0 in difierential 36 where it is combined with the wind compensation angle a as has been described.

Having described the mechanical representation of the horizontal triangle of Fig. 1, the representation of the vertical triangles which determine glide angle, altitude and depression angle of the line of sight, as shown in Fig. 2, will next be considered. The arrangement ofthis portion of the mechanism involves certain approximations which however do not appreciably affect the results obtained. A threaded rod or lead screw 99 is mounted for rotation in brackets extending upwardly from bed plate 26 with the axis of the screw at an angle to the horizontal base of the plate equal to the gliding angle of the torpedo, here taken to be 14. A travelling nut 9I is in threaded engagement with screw 99 and a bearing block 92 is mounted on nut 9| to swivel about a horizontal axis. An angle rod 93 has one leg slidable in a bearing in block 92 while the leg 93' at right angles thereto is pivoted at 94 on a slidable support member 95. Screw 59 is rotated from altitude setting knob 96 by way of splined shaft '1 and bevel gears 98. A dial 99 graduated in terms of altitude, for example, from 2000 to 50(10- feet, is gearedv to shaft 91 on which the. set altitude of release is readable with the aid of a index I00. 2 The axis of leg 93" of rod 93 as seen in elevation. represents point A of Fig. 2, that is, the projection of the present position of the target (although, in the mechanism, offset from the representation of point A in the horizontal triangle). The swivelling axis of block 92 representsthe release point O-and therefore the angle with the horizontal of the inclined portion of rod 93 is the angle of depression of the line of sight,-angle d. This angle is transmitted as an angular displacement to sight angle shaft I03 by way of horizontal leg 93 of rod 93, sector I04 and gear I85, splined to shaft I03. From shaft I03 a connection is made to tilt the sight reticle.

Support 95, slidable parallel to shaft I03 in guides (not shown) is actuated by pin 52,'represen-ting point A in the aim-off angle mechanism; througha slotted connection I06. In this manner the projection of point A in the vertical triangle is made to follow change of position of point A in the horizontal plane. Slot I05 need not be straight. For example, it may have an arcuate form with a radius equal to the average range.

ihe next portion of the mechanismito be described is that associated with the water run setting. The setting ofa predetermined ,water run is accomplished by the rotation of a knob or handle I I0 at one extremity of a shaft I I I which has threaded portions or coaxially mounted screws II2 and H3. Screw IIZ engages a threaded arm At the same. time bed plate 25, and the members of bed plate or carriage 25 while screw II3 en- I gages a threaded arm of carriage II I- on which is. pivotally mounted an arm I graduated in terms of water run, for example, from a minimum of 500 up. to 800 yards. Ar-m I28 is angularly positioned about its pivotal axis to remainparallel at all times to arm 80 by mean of helical gearing I2I driving a shaft I22 from an extensionof shaft 40 and a bevel drive from shaft I22 vto the pivot on which arm I20 is mounted.

In a plane just beneath that of arm I20 area pair of pivoted scissor-like straight edges I25, I25 urged together by a spring I26 toward a position of minimum included angle determined by stops I21, I21, cause this angle to equal the minimum angle of target approach, or angle on the bow, which the apparatus is adapted to receive. The straight inner edges of arms I25, I25v are employed as indexes. for reading the set water run on the scale of arm I20, only one edge serving as an index at. a time, as will be described.

By means of a gear I30 meshing withidler gear M of the target course setting drive, vertical shaft I3I is angularly positioned in accordance with target course. Shaft I3! mounts at its upper extremity an arm I32 carrying pin I33 adapted, upon suitable displacement, to engage either of arms I25, I25 andv upon further displacement to position the engaged arm at the angle of target approach against the opposition of spring I 26. The intersection of the edges of arm I29 and I25 or I25", as. the case may be, defines the point C of Fig. '1 and the measured length of arm I25 is proportional to the distance BC, that is to the water run. In operation, therefore, with target course set, knob. III! is rotated to match the graduation on arm [28 representing the desired water run, with the inner edge of whichever of arms, I .25, t25' intersects arm. I26,v as determined by targetc'ourse.

These stops are positioned to mounted thereon,1is moved relative to plate 26 by virtue of its threaded engagement with screw IIZ, thereby sliding the release point 0 (in the mechanism) along the line OD in accordance with the water run.

A modification of the wind compensating or drift angle mechanism is shown in Fig. 5. In this figure a selsyn receiver I35 electrically repeating. the position of a master compass or directional gyro drives, through gears I36, a spider mounting an annular member I3? concentric or coaxial with card I and bearing an index I38. In this mannerv the compass course is directly compared with position of dial I as set by handwheel 2. The drive of card I may be slightly modified in this case, for example, by causing worm 4 to engage teeth on the bottom of the card instead of at the periphery.

The exterior aspect of the computing sight and the course setting connection therefrom. to a torpedo is shown in plan in Fig. 3. The computing mechanism and parts of the sighting device are enclosed in a housing I46. The target course dial I2, bearing a representation of the target, appears in a window in the upper left-hand portion of the top of the housing with the target speed setting knob 58 centrally located with respect thereto.

The target course setting knob or handle 68 appears at the left of the dial. In the upper right portion of the housing is seen the wind setting dial I together with a portion of crank arm I2 and the indentations I for setting wind intensity. Handle or knob. 2 for orienting dial I in correspondence with the compass is seen at the right of the dial. Between the two mentioned dials there appears the light 83 which serves as an index for the proper positioning of pin 85 in slot 86 and below this light are two windows, having the form of circular sectors, through one of which is visiblethe target course arm I25 and arm I26 bearing the water run scale. The angle between the inner edges of the two windows is approximately that between arms I25 and IE5 when in engagement with their respective stops. Arm I25 isshown as displaced from the position of minimum course angle due to actuation by pin I33. When arm I215 is similarly displaced by pin- I33 it appears in the left of the two windows and serves as the index for the water run scale on arm I20 which then also appears in this window. Knob I I0 for positioning arm I20 is seen mounted atthe lower portion of the housing along side ofknob 96 for setting release altitude. Set altitude is exhibited by an index I00 cooperating with dial 99 immediately above handwheel 3t.

The torpedo rudder angle d al #6 appears through a window at the upper right of the housing with setting knob 44 adjacent. Connecting means Hi5, which may be a flexible shaft coupled to shaft 45 and provided with a. separable connection I46, transmits the compensated gyro angle 0 i a to the rudder control associated. with the gyro of a torpedo M1 having a rudder I48. Means adapted to receive an angular displacement for causing a torpedo to travel a corresponding course with respect to a reference line determined. by the torpedo gyro'are known in the art and form no part of the present invention.

The reflecting glass I50 of a reflex sight is seen at the upper portion of Fig. 3. The optics of the sight are shown. more indetail, and in connectionwith the stabilizing means therefor, in Fig. 6. The sighting means may be'directly associated with the computing mechanism-as in Fig. 3 or may be separate therefrom as in Fig. 8. In the latter case two connections are necessary for the remote control of the sight. In Fig. 8 a flexible shaft which forms an extension of or is adapted to be coupled to shaft I83 transmits the vertical angle of depression of the line of sight d while a second flexible shaft I52 which may be coupled to shaft 20 transmits the net aim-off angle 1) i a in azimuth.

Referring now to Fig. 6, there is shown a stabilizing gyro-vertical I55 mounted in a gimbal suspension, having a rotor spinning about a vertical axis and illustrated as having conventional air erection means 55. An inclined mirror I56 is mounted, preferably at an angle of 45 on an arm extending from the housing I'M of the instrument while to the rotor housing is attached a curved disc 15? having a cruciform slit constituting a reticle, a reflected image of which is seen in Fig. 3. A lamp l58 supplies illumination for the reticle and causes an image of the cross to be reflected by mirror I56 to a glass disc I50, rotatably mounted about a fixed horizontal axis l6! and normally positioned at 45 to the horizontal. An interposed lens I 59 has a suitable focal length to project the reticleimage to infinity. As the operator looks through disc l5i! coincidence of the center of the reticle image with a viewed object 7 determines the direction of a line of sight to said object. Means are provided for producing a tilt of disc 56 about its mounting axis lBl comprising arm H52, push rod I53 pivotally connected thereto, and a revolvable annular member E64 having a helical slot 965 engaging a stationary pin I56 seen in Fig. 7. Ring Hi4 may be rotated by shaft N33 (or a shaft connected thereto) by way of bevel gears lfil to raise or lower push rod I63 proportionally, against the opposition of a spring I 11!. The gyro and stabilized reticle are oriented in azimuth by the rotation of a shaft 20 (or a shaft connected thereto) through bevel gears I13, one of which is mounted on the housing H4 to which the outer gimbal ring is attached and which is rotatable on anti-friction bearings I75.

In operation, the operator sights through the transparent glass disc l5!) and sees the reticle image reflected from the surface of the glass as an illuminated cross on a darker background which eventually includes the target. Assuming that the sight and computer as a whole (or the sight alone when remotely controlled) is originally lined up with the gimbal axis on which mirrer I56 is positioned parallel with the longitudinal axis of the craft, the introduction of the net aim.. off angle, which rotates reticle I51 and mirror 55 about the gyro spin axis, requires that the craft be flown on the course OF (Fig. 1) in order to align the vertical leg of the reticle image with the center of the target. Then with sighting glass I58 displaced from a normal 45 position by the depression angle at (Fig. 2) the coincidence of the horizontal median line of the target with the horizontal leg of the reticle image signifies the proper position for the release of the torpedo to cause the torpedo to follow the predetermined collison course.

As many changes could be made in the above construction and many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

' Having described my invention, what I claim and desire to secure by Letters Patents is:

.1. In a sight for launching a gliding underwater torpedo from an aircraft, means mounted on the craft defining a line of sight, means for stabilizing said line against rotation of the craft about an axis thereof, a computing mechanism having means for orientating members therein in accordance with predetermined air and water paths of the torpedo and for determining therefrom the direction of said line at the instant of torpedo release, and means actuated by said mechanism for presetting the direction of said line of sight in accordance with said computed orientation, the subsequent sighting of the target along said line serving as a signal for the release of the torpedo.

2. In a sight for launching a gliding underwater torpedo from an aircraft, means for setting target course and speed, release altitude, water run and glide angle, a sight stabilized against rotation of the craft about a normally horizontal axis thereof including a reticle marking, means furnishing an image of said marking, said image cooperating with an image of a terrestrial object to define a line of sight to said object, and a computing mechanism actuated by the first mentioned means for moving said reticle image in a vertical plane to preset the direction of the line of sight in said plane at the instant of torpedo member and target will indicate the instant of torpedo release.

4. In a computing sight for aiming a gliding torpedo, a mechanical representation of the vector triangle having target speed as one side and a second side extending in the direction of relative speed of the torpedo and target during the water run, adjustable means for completing said triangle comprising, a member of adjustable length pivoted at an extremity of one of said two sides non-coincident with their intersection, means for adjusting the length of said last member, and means for pivotally adjusting said memher to cause the free extremity thereof to coincide with a point on the axis of the member repre senting said other side, and electrical means for indicating said coincidence.

5. Apparatus as claimed in claim 4 in which said electrical means includes cooperative contacts on the positioned member and the member engaged thereby.

6. In a computing sight for launching a gliding torpedo, a sighting device for defining a line of sight to a target, a member settable in accordance with a selected release altitude, a member representing the course and speed of the target, means for determining the effect of wind on the glide path of the torpedo, and mechanism actuated by said members and said means for adjusting said sighting device to off-set the line of sight in a direction whereby sighting of the target along said line serves as a signal for launching the torpedo.

.7. In a computing sight for launching a gliding torpedo, a sighting device for defining a line of sight to a target, means settable in accordance with the water run of the torpedo, and mechanism actuated by said means for adjusting said sighting device to off-set the line of sight in a direction whereby sighting of the target along said line serves as a signal for launching the torpedo.

8. In a computing sight for launching a gliding torpedo, a sighting device for defining a line of sight, means for positioning a. member in accordance with the underwater path of the torpedo, means for adjusting said member in accordance with the length of said water run of the torpedo, and mechanism actuated by said means for adjusting said sighting device to off-set the line of sight in a direction whereby sighting of the target along said line serves as a signal for launching the torpedo.

9. In a computing sight for launching a gliding torpedo, a sighting device for defining a line of sight, means settable in accordance with the water run of the torpedo, means settable in accordance with a desired release altitude of the torpedo, and mechanism actuated jointly by said two means for adjusting said sighting device to ofi-set the line of sight in a direction whereby sighting of the target along said line serves as a signal for launching the torpedo.

- 10. In a computing sight for launching a gliding torpedo, a sighting device for defining a line of sight to a target, a member settable in accordance with a selected release altitude, a member representing the course and speed of the target, means for determining the effect of wind on the glide path of the torpedo, means settable in accordance with the water run of the torpedo, and mechanism actuated by said members and said means for adjusting said sighting device to ofi-set said line of sight in a direction whereby sighting of the target along said line serves as a signal for releasing the torpedo.

11. In a computing sight for launching a gliding underwater torpedo from an aircraft to strike a moving target, means for determining the underwater course of said torpedo comprising a member representing the glide path of said torpedo, a member representing the underwater path of said torpedo, and means for adjusting the latter member in respect to the first member and means controlled according to the relative positions of said members for determining the angular direction of the underwater course of said torpedo.

12. In a computing sight for launching a gliding underwater torpedo from an aircraft to strike a moving target, a member representing the underwater velocity of the torpedo, a member representing the glide path of said torpedo, means for angularly adjusting said first-named member to intersect said latter member to determine the direction of said underwater course, a member representing the underwater course of said torpedo angularly positioned by saidlast-named means according to the direction of said underwater course, means for adjusting the length of said last-named member in accordance with the desired length of said underwater course, and mechanism actuated by said last-named means for adjusting the sight to off-set the line of sight in a direction whereby sighting of the target along said line serves as a signal for launching the torpedo.

13. In a computing sight for launching a gliding torpedo from an aircraft to strike a moving target, means for determining the angular directions of the air-glide and water-run of the torpedo to maintain a constant bearing relative to the target course, a sighting device defining a line of sight to said target, and a mechanism actuated by said means for adjusting said sighting device to off-set said line of sight according to said angular directions whereby sighting of said target along said line serves as a signal for launching the torpedo.

14. A computing sight as claimed in claim 13 including means for actuating said mechanism to off-set said line of sight to compensate for the effect of wind on the glide path of said torpeda MORTIMER. F. BATES. 

